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Repair plain, conventionally reinforced, or continuously reinforced Portland Cement Concrete (PCC) pavement. Repairs are either Type I, 6 ft to less than 15 ft in length; or Type II, 15 ft and greater in length.
Refer to 520.02 except as follows.
Graded Aggregate for Base Course       901.01
Crusher Run Aggregate CR-6       901.01
Concrete Mix No. 9       902.10
Nonshrink Grout       902.11(c)
Epoxy Grout       902.11(d)
Epoxy Adhesive       921.04
Concrete Mix HE       902.10
Macro Polyolefin Fibers       902.15.01
522.02.01 Polyester Grout. A polyester grout may be used in lieu of epoxy grout, provided the grout conforms to 902.11(d). Identify cartridge type systems by batch or lot number.
522.02.02 Epoxy Adhesives. Refer to 921.04. Use water insensitive materials classified as Type V, Grade 3, Class B and C.
522.02.03 Reinforcement. Refer to Section 908 for reinforcement, including load transfer assemblies, tie bars, deformed steel bars, and longitudinal tie devices, except all material shall be epoxy coated.
The Engineer will determine the areas to be repaired and the type of repair. Submit a proposed repair plan, including equipment, methods, and procedures prior to the start of repairs. If repairs cover multiple lanes, ensure that the longitudinal joints are established according to Standard No. MD 572.92 in the same location. Protect the area against damage from all causes. Repair or replace any part of the repaired pavement that is damaged.
522.03.01 Equipment. Refer to 520.03.01 and the following.
522.03.01.01 Drills. For dowel bar holes along transverse joints, use hydraulic gang drills with a minimum of two independently powered and driven drills. Use tungsten carbide drill bits. Control the forward and reverse travel of the drills by mechanically applied pressure. Mount the drill on a suitable piece of equipment such that it is quickly transported and positioned. Rest and reference the drill rig frame on and to the pavement surface such that the drilled holes are cylindrical, perpendicular to the surface being drilled, and repeatable in terms of position and alignment on the surface being drilled. Hand-held drills are not permitted for transverse joints.
For tie-bar holes along longitudinal joints, hand-held drills are permitted.
522.03.01.02 Match Curing Apparatus. According to R 72.
522.03.01.03  Portable Compressive Strength Testing Machine. Refer to T 22. Provide testing machines on site for testing match cure specimens at the specified times.
522.03.02 Weather Restrictions. Refer to 520.03.02, except perform the work only during April through October.
Provide cold weather protection as specified in 520.03.12, when the ambient air temperature is less than 70 F. The 96-hour cure time for cold-weather applications does not apply. Refer to 522.03.11.
522.03.03 Saw Cuts and Removal of Existing Pavement. Make all saw cuts perpendicular using a diamond saw blade. Remove concrete slabs by the lift out method in large sections. No other method of slab removal shall be used unless approved. Repair adjacent slab damage caused by the removal operations. Repair spalls greater than 1/4 in. wide, 2 in. long, and more than 1/2 in. deep below the pavement surface using an approved epoxy mortar. Extend the patch boundary by re-sawing the limits of the patch beyond the spalled area when spalls greater than 1 in. wide, 12 in. long, and more than 1/2 in. deep below the pavement surface are created by the pavement removal operation. Complete all repairs within the same day that the pavement is removed.
Perform saw cutting and pavement removal as follows:
(a) Plain and Conventionally Reinforced Portland Cement Concrete Pavement. Make full depth saw cuts for the full slab width. When the repair is on only one side of an existing transverse joint, extend removal into the adjacent slab a sufficient distance to remove existing dowels. Remove the concrete slab within one week after making the saw cuts.
(b) Continuously Reinforced Portland Cement Concrete Pavement. Locate the boundaries of the repair at least 12 in. from the nearest transverse tight crack. Make a full depth saw cut across the full width of the slab. Remove the concrete to its full depth within the boundaries of the repair area within 72 hours after making saw cuts.
When saw cuts close due to temperature, make narrowly spaced, full depth, and full width saw cuts to relieve the pressure, or as directed. Remove the material between the narrowly spaced saw cuts and between the longitudinal joints as specified. Remove all waste material from the repair site. Seal any saw cuts that extend into adjacent slabs, curbs, or gutters as specified in Section 523.
522.03.04 Base, Subbase and Subgrade Preparation. Refer to 505.03.05, except moisten the subbase or subgrade for all types of repairs.
Backfilling may be done with aggregate or concrete.
522.03.05 Subgrade Drains. Construct subgrade drains as specified in Section 306, if directed.
522.03.06 Forms. Use the existing adjacent pavement as a form. Ensure the adjacent pavement surfaces match the existing concrete pavement surface prior to performing repairs.
If the adjacent shoulder becomes damaged during removal of existing pavement, use forms conforming to 520.03.04. Excavate the adjacent shoulder the width of the form plus 6 in. Overlap existing pavement at least 1 ft on each side of the patch and securely fasten to prevent movement. After removing the form, repair the excavated shoulder using the same type of material as used in the original shoulder.
522.03.07 Reinforcement. Refer to 520.03.06 and as specified. Place the doweled joint at the slab face closest to the original doweled joint location.
(a) Refer to Standard No. MD 577.08. Drill holes into the face of the existing slab as close as possible to mid depth, avoiding existing reinforcing steel. After cleaning out the holes, make sure the surface is dry before applying epoxy.
(b) Grout or epoxy the dowels and tie bars into place. Align reinforcement in the direction of the pavement and parallel to the surface.
(c) Drill four holes per wheel path (eight per lane) into the face of the existing slab at mid depth. Space holes 12 ± 1 in. apart on center.
(d) Use a pachometer or other device to determine the location and length of longitudinal joint tie bars in the concrete to remain in place outside the repair area.
(e) If a longitudinal joint tie bar is within 12 in. of the surface being drilled, drill the outer holes 3 in. to 4 in. from the end of the tie.
(f) If no tie bars are within 12 in. of the surface being drilled, drill the outer holes 12 in. from a longitudinal joint between two travel lanes and 12 in. from a longitudinal joint between a travel lane and a shoulder.
Place a plastic grout retention disk on each dowel to prevent loss of the bonding material. Coat the protruding ends of the dowel bars with an approved water insoluble lubricant.
522.03.08 Joints. Refer to 520.03.14, except that joints shall not be sealed.
522.03.09 Concrete Placement. Refer to 520.03.07. Clean any adjacent vertical surfaces prior to concrete placement. Construct both plain and continuously reinforced concrete pavement repairs in one full depth operation. Construct conventionally reinforced concrete pavement repairs by placing two equal lifts with the wire mesh laid on the surface of the first lift. Vibrate all concrete.
522.03.10 Finishing. Strike off the surface of the placed concrete to the finished grade using an adjustable steel or wooden template then float the surface. Screed the repair to provide ride uniformity with the adjacent pavement, as necessary. Match the contour of the existing roadway. Perform surface checks as specified in 520.03.10. Patches not meeting uniformity requirements shall be diamond grinded at no additional cost.
522.03.11 Curing. Cure the concrete as specified in 520.03.12, except continue curing for 12 hours after concrete placement or until the repair is put into service. The requirement for an approved spraying machine having drive-wheels is waived when using the liquid membrane forming compound method.
522.03.12 Emergency Filler. Provide a sufficient amount of CR-6 to fill the void of the repair area. Place and compact the material then cover it with a steel plate. Completely remove the material when proceeding with the work using procedures that will not disturb the subgrade, subbase, dowels, load transfer tie bars, load transfer assemblies, or previously placed reinforcement.
522.03.13 Steel Plates. Have an ample supply of 1 in. thick steel plates of sufficient length and width available on the project to cover emergency filler and to protect the patch area until the concrete has developed sufficient strength to carry traffic.
522.03.14 Unacceptable Repairs. Remove and replace repairs that are not in conformance and repairs damaged by traffic or other causes. Repair limits for damages shall be as specified in 522.03.03.
522.03.15 Opening to Traffic. When used, prepare match cure specimens according to R 72. Provide temperature readings of the test specimens and the corresponding patch after finishing at intervals of one hour or less. Test match cure specimens on site at specified ages with a portable compression testing machine certified within 12 months. The pavement may be opened to traffic after having attained a compressive strength of 2000 psi, and as approved.
Portland cement concrete pavement repairs will be measured in place and paid for at the Contract unit price per square yard for the pertinent type Plain Portland Cement Concrete Pavement Repair, Conventionally Reinforced Portland Cement Concrete Pavement Repair, and Continuously Reinforced Portland Cement Concrete Pavement Repair item. The payment will be full compensation for saw cuts, furnishing, hauling, placing of all materials, curing using match cure apparatus, field testing of match curing specimens, removal and disposal of old concrete, grout, drilled holes, chairs, all tie devices, reinforcement, epoxy coating, steel plates, emergency filler, joint sealing, and for all material, labor, equipment, tools, and incidentals necessary to complete the work.
Emergency filler, match curing apparatus, portable compression testing device, and steel plates will remain the property of the Contractor at the completion of the project. Damages caused by the Contractor shall be repaired at no cost to the Administration.
522.04.01  Removal of unsuitable material will be measured and paid for as Class 1-A Excavation. Refill will be measured and paid per cubic yard for aggregate or concrete.
522.04.02  Subgrade drains will be measured and paid for as specified in the applicable portions of Section 306.